Voltage-gated Cav channels mediate activity-dependent Ca2+ signals required for gene transcription and neurotransmission. Ca2+-dependent inactivation and facilitation (CDI and CDF, respectively) allow Cav channels to adjust Ca2+ influx according to neuronal activity, thereby fine-tuning Ca2+ signals that control neuronal excitability and synaptic plasticity. The rationale for the proposed research is that defining how Cav channels generate and maintain Ca2+ signals will answer longstanding questions regarding the heterogeneous properties of Cav channels in neurons and enable new mechanistic inquiries into the roles of specific Cav channels in orchestrating the normal development and function of the nervous system. The expected outcomes of the proposed research are: establishment of a new role for calretinin as a dynamic regulator of effectors including Cav2.1 (Aim 1); and elucidation of a mechanism responsible for the long-lasting properties and functional impact of neuronal Cav1 L-type currents (Aim 2). We believe that the proposed research will make a lasting and positive impact: the Cav channel regulatory mechanisms it will define will likely facilitate the development of novel therapeutics for neurological and neuropsychiatric disorders resulting from dysregulation of neuronal Ca2+ signals.